Red azo dye.



UNITED STATES PATENT OFFICE;

SIGNORS TO AOTIEN GESELLSOHAFT FUR ANILIN BERLIN, eERMANY.

FABRIKATION, OF

RED AZO DYE.

SPECIFICATION forming part of Letters Patent No. 704,825, dated July 15, 1902.

Application filed March 3, 1902.

To all whom it may concern.

Be it known that we, WILHELM H ERZBERG and Orro SIEBERT, of Berlin, in the Kingdom of Prussia, German Empire, have invented new and useful Improvements in the Production of Red Azo Dyes; and we do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

We have discovered that para-substituted meta amido -alphyl sulfamido compounds represented by the typical formulal NH so2- Alphyl (in which X means a substituted group, R and R hydrogen atoms, which may be re placed by alkyl radicals) constitute most valuable components for the production of azo dyestuffs when combined with diazotized para-nitro-ortho-amido-salicylic acid represented by the formula The dyestuffs thus formed dye wool directly in an acid-bath yellowish-red shades. If the Serial No. 96,446. (Specimens-l para-substituted mono alkylated or asymmetrically dialkylated meta diamin of the benzene series with an aromatic sulfochlorid.

In the first case a subsequent reduction is necessaryin order to convert the nitro group into an amido group. For instance, the orthoamido-para-toluol-para-s ulfamidmtoluol represented by the typical formula-- plete the reaction, six parts of sodium carbonate are gradually added. The condensation product thus formed may be directly filtered 0E. It is purified by re-solution in diluted alkali lye and reprecipitation by means of hydrochloric acid. It melts at 164 centigrade. In order to transform this nitro compound into the corresponding amide compound, it is subjected to the action of zincdust and hydrochloric acid or any propriate reducing agent.

The new product dissolves easily in diluted alkalies, as well as in diluted mineral acids. From the solutions thus obtained it may be precipitated by the addition of acetic acid or sodium acetate, respectively. It forms a white crystalline powder, melting at 160 centigrade.

- The following example, in which the parts are by weight, may serve to illustrate the preparation of our new dyestuffs.

ExampZeMamtfacture of an azo dyesiufi from para. m'tro orzho amtdosaZic-ylic acid and oriho-amidog9ara-toluoZ-pam-sufiamidotoluoL-Teu parts of para-nitro-ortho-amidm salicylic acid are diazotized in the well-known other apway, and the diazo solution thus obtained is slowly run into a solution prepared by dissolving 13.8 parts of ortho-amido-para-toluolpara-sulfamidotoluol in five hundred parts of water and two parts of caustic soda while separates directly. It is filtered, pressed, and dried. It forms in the dry state a reddish-brown powder with metallic luster,which dissolves readily in warm water, forming a reddish-brown solution. The aqueous solution turns deep red on addition of causticsoda lye and assumes a light orange-red coloration on addition of hydrochloric acid. The dyestuff dissolves easily in concentrated sulfuric acid with a dark yellowish-red coloration. The alcoholic solution is yellowish red. The dyestuff produces on wool with the aid of chromium mordants intense yellowishred shades, remarkable for their fastness to soaping and milling and to the action of light and sulfurous acid.

The result is not materially changed if for the ortho-amido-para-toluol-para-sulfamidotoluol employed in the preceding example an equimolecular proportion of ortho monoethyl amido para toluol-para-sulfamido-toluol melting at 120 centigrade is substituted.

Having thus described our invention and in what manner the same is to be performed,

what we claim as new is- 1. The herein-described new azo dyestuffs which are sodium salts of acids having the formula:

(in which X means asubstituting group, and

R and R hydrogen atoms, which may be re-' dyestuffs forming in the dry state reddishbrown powders, readily soluble in warm water, forming reddish brown solutions; the aqueous solutions turning deep red on addistirring well and keeping the mixture weakly alkaline by the addition of caustic-soda lye. The new dyestufi, which is a sodium salt of an acid having the formula tion of caustic-soda lye and assuming a light orange-red coloration on addition of hydrochloric acid; the dyestuffs dissolving readily in concentrated sulfuric acid to dark yellowish-red solutions, and in alcohol to yellowishred solutions; the dyes producing on wool with the aid of chromium mordants yellowish red shades of great intensity and fastness.

2. The herein described how dyestufi, which is a sodium salt of an acid having the formula:

0 H, 2 1 I=No.,.H

lye and assuming a light orange-red coloration on addition of hydrochloric acid; the dyestuff dissolving readily in concentrated sulfuric acid to a dark yellowish-red solution, and in alcohol to a yellowish-red solution; the dye producing on wool with the aid of chromium mordants yellowish-red shades of great intensity and fastness.

In witness whereof we have hereunto signed our names, thisl-Sth day of February, 1902, in the presence of two subscribingwitnesses.

WILHELM HERZBERG. OTTO SIEBERT.

Witnesses WOLDEMAR HAUPT, HENRY I'IASPER. 

